1. Field of the Invention
This invention relates, generally, to an apparatus that sorts envelopes into separate bundles. More particularly, it relates to a sorter that arranges envelopes into bundles that are laterally offset from one another.
2. Description of the Prior Art
Eleven digit ZIP codes include a five digit ZIP code that identifies a geographical area, a four digit extension code that identifies a particular residence or building within that geographical area, and a two digit extension code that identifies a particular postal delivery route.
Sorting machines heretofore known sort envelopes bound for different postal delivery routes by providing a spatial separation between contiguous bundles. All of the envelopes within a particular bundle are staggered on a conveyor belt by a small amount, such as an eighth of an inch, and contiguous bundles are spaced apart from one another by an inch or so. A worker carefully observes the bundles as they arrive on a conveyor belt at an unloading station, scoops them up, and places a rubber band around them. This is a time-consuming procedure because the worker must scoop up the envelopes and jog them to place them into a neat alignment; the application of a rubber band also takes time.
One of the problems with this well-known sorting method is that envelopes are often skewed when they arrive at the worker's station. The skew is typically such that the leading end of an envelope will be positioned within a leading bundle, and the trailing end of the envelope will be positioned within a trailing bundle. Thus, a worker unloading the belt will be unsure as to which bundle a skewed envelope belongs, and time will be spent trying to identify to which bundle it belongs. This increases labor costs, and even with the expenditure of extra time, mistakes will be made.
Recent developments in the art include marking the last envelope in a bundle with a strip of red ink along its top edge to clearly identify the last envelope of a bundle. However, this requires workers to maintain the ink supply, and problems associated with the use of ink inevitably arise. Moreover, the red mark detracts from the aesthetic appeal of the mailing. For example, if an advertiser is mailing attractive envelopes, it will not be pleased that a significant number of its envelopes are being marked and rendered less attractive.
What is needed, then, is an improved means for separating contiguous bundles from one another. The improved method should produce bundles that are unambiguously separated from one another and therefore not require a worker to decide to which bundle a skewed envelope should be assigned. Nor should it require the use of ink. The improved method should reduce labor costs by eliminating the time-consuming steps of requiring a worker to scoop up bundles and to jog them before applying a rubber band around them. Instead, it should reduce the amount of labor required by producing neatly-aligned, unambiguous bundles that are ready for banding.
There are two types of machines with which an improved sorting apparatus could be used. A first type of machine inserts sheets into envelopes at a high rate of insertions per hour and delivers envelopes to a discharge table where the envelopes are then manually sorted and bundled by wrapping a rubber band around the individual bundles. A second type of machine sorts envelopes that are ready to be mailed into a plurality of bins, where each bundle sorts into an individual bin. A worker removes the bundles from a bin, places a rubber band about each bundle, and places the banded bundle in a tray for delivery to various postal carriers.
There is a need for a sorting apparatus having utility with both types of machines.
However, it was not obvious to those of ordinary skill in this art how the needed apparatus could be provided, in view of the art considered as a whole at the time the present invention was made.